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Synergic degradation of diesel by Scirpus triqueter and its endophytic bacteria Full text
2014
Zhang, Xinying | Chen, Lisha | Liu, Xiaoyan | Wang, Chuanhua | Chen, Xueping | Xu, Gang | Deng, Kaifang
The endophytic bacterium isolated from Scirpus triqueter was proved to be an oil-degraded bacterium. A pot experiment was conducted to investigate the removal ratio of diesel under the combined effect of oil-degraded microorganism (Pseudomonas sp. J4AJ) and S. triqueter. The effect of diesel on plant growth parameters, soil enzymes and microbial community was assessed after 60 days. The results showed that the soils which were planted with S. triqueter and inoculated with J4AJ displayed the highest removal ratio (54.51 ± 0.15 %) after 60-day experiment. However, the removal ratio of J4AJ-treated soils was 38.97 ± 0.55 %. Diesel was toxic to S. triqueter, as evidenced by growth inhibition during the experimental period. However, the plant height and stem biomass in the soils inoculated with J4AJ significantly increased. The combined effect of S. triqueter and J4AJ improved the enzyme activities of the catalase and dehydrogenase in the contaminated soil. The diversity index in soils under the effect of S. triqueter combined with J4AJ was lower than that of the other soil samples. The principal analysis of phospholipid fatty acid signatures revealed that the combined effect of S. triqueter and J4AJ increased the differences of soil microbial community structure with the other treatments.
Show more [+] Less [-]Assessing spatial distribution, sources, and human health risk of organochlorine pesticide residues in the soils of arid and semiarid areas of northwest China Full text
2014
Huang, Tao | Guo, Qiang | Tian, Hui | Mao, Xiaoxuan | Ding, Zhongyuan | Zhang, Gan | Li, Jun | Ma, Jianmin | Gao, Hong
Thirty-two topsoil samples were collected to analyze the residue levels of organochlorine pesticides (OCPs) in topsoil of arid and semiarid areas of northwest China in 2011. Results showed that DDTs were the dominant contaminants with a mean concentration of 12.52 ng/g. The spatial distribution characteristics indicated that α-hexachlorocyclohexanes (HCHs) were mainly used in rural sites, whereas hexachlorobenzene (HCB) and endosulfan were detected mostly in urban areas. DDTs, heptachlor, and chlordane were found almost equally in both urban and rural areas. Source identification revealed that the current levels of HCHs in soils were attributable to the residues from their historical use and fresh usage of lindane (γ-HCH). DDTs were mainly from historical use and fresh usage of dicofol, and HCB was emitted from the chemical industry. It was also found that the current soil levels of heptachlor were mainly from its historical usage, endosulfan from fresh input, and chlordane from long-range atmospheric transport, respectively. The noncarcinogenic health risk assessment with a model was also conducted using USEPA standards for adults and children. Results indicated that health risk under nondietary exposure to OCPs decreased in the sequence of ΣDDT > ΣHCH > HCB > Σheptachlor > Σendosulfan > Σchlordane. According to the reference dose from the USEPA, the health risk under nondietary exposure to OCPs in the soil samples was at a relatively safe level.
Show more [+] Less [-]Long-term monitoring and modeling of polychlorinated dibenzo-p-dioxins and dibenzofurans from municipal solid waste incinerators and surrounding area in northern Taiwan Full text
2014
Mi, Hsiao-Hsuan | Wang, Wanru | Lin, Sheng-Lun | Lai, Yi-Chieh | Mwangi, John Kennedy | Wang, Lin Chi | Chang-Chien, Guo-Ping
Municipal solid waste incinerators (MSWIs) have long been the major contributors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to ambient air in Taiwan. After stringent MSWI emission standards were introduced in 2001, the long-term continuous monitoring of flue gas and ambient air quality became necessary to ensure the effectiveness of the related control strategies. Three MSWIs and the surrounding ambient air were investigated in the current study for PCDD/F characteristics during 2006 to 2011. The average concentrations in the flue gas ranged from 0.008 ~ 0.0488 ng I-TEQ/Nm³, which is much less than the emission standard in Taiwan (0.1 ng I-TEQ/Nm³) (I-TEQ is the abbreviation of International Toxic Equivalent). This led to extremely low levels in the ambient air, 0.0255 pg I-TEQ/Nm³, much less than the levels seen in most urban areas around the world. Additionally, the results obtained using the Industrial Source Complex Short-Term Dispersion Model (ISCST3) indicate that the PCDD/F contributions from the three MSWIs to the ambient air were only in the range from 0.164 ~ 0.723 %. Principal component analysis (PCA) showed that the PCDD/Fs in the air samples had very similar characteristics to those from mobile sources. The results thus show that stringent regulations have been an effective control strategy, especially for urban areas, such as Taipei City.
Show more [+] Less [-]Mar Piccolo of Taranto: Vibrio biodiversity in ecotoxicology approach Full text
2014
Narracci, M. | Acquaviva, M. I. | Cavallo, R. A.
Microorganisms play an indispensable role in the ecological functioning of marine environment. Some species are sensitive while others are insensitive for a specific pollutant. The aim of this work is a preliminary study of the quantitative and qualitative distribution of cultivable vibrios in sediments and water samples characterized by different toxicity levels. For 1 year, in three suitably selected sampling stations of Mar Piccolo in Taranto (Ionian Sea, Italy), we have evaluated the toxicity level by Microtox® system, vibrios, total, and fecal coliform densities. The results of the Microtox® tests showed sediments characterized by an elevated level of toxicity, while the interstitial water of the same sites always showed biostimulatory phenomenon. The quantitative results show that vibrios and coliforms are more abundant in water than in sediment samples. The most often isolated strains were: Vibrio alginolyticus, Vibrio mediterranei, Vibrio metschinkovii, and Vibrio splendidus II. This work is the first example of study on the distribution of Vibrio species related to toxicity evaluation conducted by the Microtox® bioassay. The results show the different distribution of Vibrionaceae in two environmental matrices analyzed and characterized by different levels of toxicity.
Show more [+] Less [-]Sublethal Cd-induced cellular damage and metabolic changes in the freshwater crab Sinopotamon henanense Full text
2014
Xuan, Ruijing | Wu, Hao | Li, Yingjun | Wang, Jinxiang | Wang, Lan
To explore whether sublethal cadmium (Cd) exposure causes branchial cellular damages and affects the metabolic activity in brachyuran crustaceans, the freshwater crab Sinopotamon henanense was exposed to 0.71, 1.43, and 2.86 mg/L Cd²⁺for 3 weeks. Gill morphology, metabolic activity (activities of isocitrate dehydrogenase (IDH), cytochrome c oxidase (CCO) and lactate dehydrogenase (LDH), mRNA expression of CCO active subunit 1 (cco-1) and ldh, as well as ATP levels) in crab muscle were investigated. The results showed that sublethal Cd exposure caused profound morphological damages in the gills. The branchial epithelial cells were disorganized and vacuolized. Ultrastructurally, a decrease in number of apical microvilli, vacuolized mitochondria, and condensed chromatin were observed in gill epithelial cells. Correspondingly, the Cd exposure also induced downregulations of cco-1 and ldh mRNA expression and reduced activities of IDH, CCO, and LDH, in accordance with the lower ATP level in crab muscle. These results led to the conclusion that gill damage caused by sublethal Cd exposure could lead to an impairment of oxygen uptake of S. henanense, and the inhibition of metabolic activity decreases the oxygen demand of the crab and assists them to survive under the condition of lower oxygen availability. These effects add to our understanding on toxic effects of Cd and survival management of S. henanense subchronically exposed to sublethal Cd.
Show more [+] Less [-]Economically oriented process optimization in waste management Full text
2014
Maroušek, Josef
A brief report on the development of novel apparatus is presented. It was verified in a commercial scale that a new concept of anaerobic fermentation followed by continuous pyrolysis is technically and economically feasible to manage previously enzymatically hydrolyzed waste haylage in huge volumes. The design of the concept is thoroughly described, documented in figures, and biochemically analyzed in detail. Assessment of the concept shows that subsequent pyrolysis of the anaerobically fermented residue allows among biogas to produce also high-quality biochar. This significantly improves the overall economy. In addition, it may be assumed that this applied research is consistent with previous theoretical assumptions stating that any kind of aerobic or anaerobic fermentation increases the microporosity of the biochar obtained.
Show more [+] Less [-]Growth inhibition of bloom forming cyanobacterium Microcystis aeruginosa by green route fabricated copper oxide nanoparticles Full text
2014
Sankar, Renu | Prasath, Barathan Balaji | Nandakumar, Ravichandran | Santhanam, Perumal | Shivashangari, Kanchi Subramanian | Ravikumar, Vilwanathan
The cyanobacterium Microcystis aeruginosa can potentially proliferate in a wide range of freshwater bionetworks and create extensive secondary metabolites which are harmful to human and animal health. The M. aeruginosa release toxic microcystins that can create a wide range of health-related issues to aquatic animals and humans. It is essential to eliminate them from the ecosystem with convenient method. It has been reported that engineered metal nanoparticles are potentially toxic to pathogenic organisms. In the present study, we examined the growth inhibition effect of green synthesized copper oxide nanoparticles against M. aeruginosa. The green synthesized copper oxide nanoparticles exhibit an excitation of surface plasmon resonance (SPR) at 270 nm confirmed using UV–visible spectrophotometer. The dynamic light scattering (DLS) analysis revealed that synthesized nanoparticles are colloidal in nature and having a particle size of 551 nm with high stability at −26.6 mV. The scanning electron microscopy (SEM) analysis shows that copper oxide nanoparticles are spherical, rod and irregular in shape, and consistently distributed throughout the solution. The elemental copper and oxide peak were confirmed using energy dispersive x-ray analysis (EDAX). Fourier-transform infrared (FT-IR) spectroscopy indicates the presence of functional groups which is mandatory for the reduction of copper ions. Besides, green synthesized copper oxide nanoparticles shows growth inhibition against M. aeruginosa. The inhibition efficiency was 31.8 % at lower concentration and 89.7 % at higher concentration of copper oxide nanoparticles, respectively. The chlorophyll (a and b) and carotenoid content of M. aeruginosa declined in dose-dependent manner with respect to induction of copper oxide nanoparticles. Furthermore, we analyzed the mechanism behind the cytotoxicity of M. aeruginosa induced by copper oxide nanoparticles through evaluating membrane integrity, reactive oxygen species (ROS), and mitochondrial membrane potential (Δψm) level. The results expose that there is a loss in membrane integrity with ROS formation that leads to alteration in the Δψm, which ends up with severe mitochondrial injury in copper oxide nanoparticles treated cells. Hence, green way synthesized copper oxide nanoparticles may be a useful selective biological agent for the control of M. aeruginosa.
Show more [+] Less [-]Capability of the natural microbial community in a river water ecosystem to degrade the drug naproxen Full text
2014
Grenni, Paola | Patrolecco, Luisa | Ademollo, Nicoletta | Di Lenola, Martina | Barra Caracciolo, Anna
The present work aims at evaluating the ability of the River Tiber natural microbial community to degrade naproxen in water samples collected downstream from a wastewater treatment plant. For this purpose, different water microcosms were set up (microbiologically active vs sterile ones) and treated with naproxen (100 μg/L) alone or in the co-presence of gemfibrozil in order to evaluate if the co-presence of the latter had an influence on naproxen degradation. The experiment was performed in the autumn and was compared with the same experimental set performed in spring of the same year to highlight if seasonal differences in the river water influenced the naproxen degradation. Pharmaceutical concentrations and microbial analysis (total cell number, viability, and microbial community composition) were performed at different times in the degradation experiments. The overall results show that the natural microbial community in the river water had a key role in the naproxen degradation. In fact, although there was a transient negative effect on the natural microbial community in all the experiments (3 h after adding the pharmaceutical), the latter was able to degrade naproxen within about 40 days. On the contrary, no decrease in the pharmaceutical concentration was observed in the sterile river water. Moreover, the co-presence of the two drugs lengthened the naproxen lag phase. As regards the natural microbial community composition detected by Fluorescence in situ Hybridization, Alpha and Gamma-Proteobacteria increased when the pharmaceutical halved, suggesting their role in the degradation. This study shows that with the concentration studied, naproxen was degraded by the natural microbial populations collected from a river chronically contaminated by this pharmaceutical.
Show more [+] Less [-]Uranyl–water-containing complexes: solid-state UV-MALDI mass spectrometric and IR spectroscopic approach for selective quantitation Full text
2014
Ivanova, Bojidarka | Spiteller, M. (Michael)
Since primary environmental concept for long storage of nuclear waste involved assessment of water in uranium complexes depending on migration processes, the paper emphasized solid-state matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) and IR spectroscopic determination of UO₂(NO₃)₂·6H₂O; UO₂(NO₃)₂·3H₂O, α-, β-, and γ-UO₃ modifications; UO₃·xH₂O (x = 1 or 2); UO₃·H₂O, described chemically as UO₂(OH)₂, β- and γ-UO₂(OH)₂ modifications; and UO₄·2H₂O, respectively. Advantages and limitation of vibrational spectroscopic approach are discussed, comparing optical spectroscopic data and crystallographic ones. Structural similarities occurred in α–γ modifications of UO₃, and UO₂(OH)₂ compositions are analyzed. Selective speciation achieved by solid-state mass spectrometry is discussed both in terms of its analytical contribution for environmental quality assurance and assessment of radionuclides, and fundamental methodological interest related the mechanistic complex water exchange of UO₃·H₂O forms in the gas phase. In addition to high selectivity and precision, UV-MALDI-MS, employing an Orbitrap analyzer, was a method that provided fast steps that limited sample pretreatment techniques for direct analysis including imaging. Therefore, random and systematic errors altering metrology and originating from the sample pretreatment stages in the widely implemented analytical protocols for environmental sampling determination of actinides are significantly reduced involving the UV-MALDI-Orbitrap-MS method. The method of quantum chemistry is utilized as well to predict reliably the thermodynamics and nature of U–O bonds in uranium species in gas and condensed phases.
Show more [+] Less [-]Catalytic hydrolysis of urea from wastewater using different aluminas by a fixed bed reactor Full text
2014
Shen, Shuguang | Li, Meina | Li, Binbin | Zhao, Zhijun
In order to find an effective method for treating urea wastewater, the experiments on the hydrolysis of urea in wastewater were conducted in a fixed bed reactor with different aluminas (α-Al₂O₃, γ-Al₂O₃, and η-Al₂O₃) as catalysts respectively in contrast with inert ceramic particle. The results indicate that the three alumina catalysts show obvious catalytic activity for urea hydrolysis at 125 °C. The order of activity is η-Al₂O₃ > γ-Al₂O₃ > α-Al₂O₃, and the activity difference increases with increasing temperature. According to the characterization results, surface acidity has little impact on the activity of catalyst. However, it was found that surface basicity of alumina catalyst plays an important role in catalytic hydrolysis of urea, and the activity of catalyst may be also influenced by the basic strength. With η-Al₂O₃ as catalyst, the urea concentration in wastewater is reduced to 4.96 mg/L at a temperature of 165 °C. Moreover, the η-Al₂O₃ shows a good stability for urea hydrolysis. The hydrolysis of urea over η-Al₂O₃ catalyst can evidently reduce the reaction temperature and is promising to replace industrial thermal hydrolysis process.
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